Thermostatic circuit-closer



J. M. JOHNSON. THEBMOSTATIC CIRCUIT CLOSER. APPLICATION FILED JAN.25, 1919.

Patented Nov. 2, 1920.

3 mn m M m w ATTORNEY.

WITNESS: x

UNITED STATES PATENT OFFICE.

JOHN M. JOHNSON, OF KANSAS CITY, MISSOURI, ASSIGNOR TO THE UNITED STATES AUTOMATIC FIRE ALARM COMPANY, OF KANSAS CITY, MISSOURI, A CORPORATION OF MISSOURI.

THERMOSTATIC CIRCUIT-CLOSER.

Specification of Letters Patent.

Application filed January 25, 1919. Serial No. 273,036.

fl '0 all to 7mm it may concern Be it known that 1, JOHN M. JoHNsoN, a

V citizen of the United States, residing at Kansas City, in the county of Jackson and State of Missouri, have invented certain new and useful Improvements in Thermostatic Circuit-Closers, of which the following is a specification.

My invention relates to improvements in thermostatic circuit closers, and one object is to provide a new and useful device of this character of simple and inexpensive construction and positive in action.

A further object is to provide a device of this character which may be used to advantage in different circuits and is especially useful when employed in fire alarm systems.

Another object is to provide a thermostat which is hermetically sealed to protect the internal parts from corrosion and other detrimental effects produced by exposure to the outer atmosphere.

Other objects and advantages will hereinafter appear, and in order that-the invention may be fully understood, reference will now be made to the accompanying drawings, in which:

Figure 1 is an elevation of the device.

Fig. 2 is an irregular sectional view of the device set ready for operation and taken on line 11-11 of Fig. 4.

Fig. 3 is a longitudinal sectional view after the device has operated and is taken on line III-III of Fig. 1.

Fig. 4 is a plan view of the device.

Fig. 5 is a diagram of a portion of a circuit embodying one of the circuit closures.

In carrying out the invention, I employ a base 1 consisting, preferably, of porcelain or other insulating material having holes 2 for the passage of screws or other devices whereby it may be secured to the wall or ceiling of a building.

4 designates a tube secured within the base 1. and consisting, preferably, of glass or other transparent material, so that the contacts of the device may be observed.

6 designates a conductor, the greater portion of which is inclosed within the tube 4 and hermetically sealed with wax 8 to ex clude the outer atmosphere. The wax 8 is placed in peripheral grooves 10 formed in said conductor 6. The lower portion of the conductor 6 is provided with a peripheral flange 11., which abuts the inturned flange of a ferrule 13 which coacts with the wax 8 in holding the tube 4 and the conductor 6 together.

12 designates a large longitudinal opening in the conductor 6 to receive the working parts of the'thermostat embodying a plunger 14 and a coil spring 16, which latter is interposed between one end of the opening 12- and a movable contact 18 adjustably secured to said plunger 14 by a set screw 20, so that it may be adjusted to regulate the tension on the spring 16 as desired.

The plunger 14 is slidably mounted within axial bores 22 of the conductor 6 and normally held in raised position by a disk 24 secured by fusible solder 26 to the lower end of the conductor 6. By thus holding the plunger in raised position, the spring 16 is held under compression and the movable contact 18 is held out of engagement with two stationary contact points 30 projecting upwardly from a block of insulation 32 seated in the lower end of the opening 12.

A pair of insulated wires 34 lead upwardly from. the contacts 30 to a plate 36 provided with a binding post 38 extending through the base 1 and having a nut 40 threaded on its lower end to secure a circuit wire 42 upon said binding post 38. A longitudinal groove 39 is provided in the upper portion of the conductor 6 for the passage of the wires 34.

Plates 44 are secured to the upper end of the conductor 6'and provided with binding posts 46, which extend through the base 1 and are provided with nuts 48 to secure the adjacent ends of a circuit wire 49 thereto. The plates 36 and 44 and the upper end of the conductor 6 are hermetically sealed with suitable means such as wax 50 toprotect them from corrosion, etc.

In practice when the thermostat is employed in a house circuit, such as disclosed on Fig. 5 and described in U. S. Patent No. 1,174,503, of March 7, 1916, the current normally flows from one of the mains 62, through the wires 49, the plates 44, the conductor 6, the electromagnet 60, and back to the other main 62 through the wires 42 and the plate 36. Should a fire occur and melt the fuse, the plunger 46 carries the contact 18 into engagement with the contacts 30 and short-circuits that portion of the house circuit at the left of the thermostat and containing the electromagnet 60.

By employing a spring to force the plunger downwardly, it is apparent that the sensitii eness of the device can be increased by increasing the compression of said spring through proper adjustment of the contact 18 upon the plunger 14.

From the foregoing description it will be understood that I have provided a thern1ostat well adapted for the purpose intended, and while I have shown and described the preferred form of the invention, I reserve the right to make such changes in the construction, combination, and arrangement oi? parts as properly fall within the spirit and scope of the claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent, is:

1. In a device oi the character described, a base, a tube secured within said base, a conductor sealed within said tube and provided near one end with a longitudinal groove, a stationar contact disposed within said conductor but insulated therefrom, an insulated wire extending through said groove from the stationary contact, a plate on the base to which said wire is connected, a binding post fixes to said plate, a movable contact in circuit with the conductor and tending to engage said stationary contact, and fusible means normally holding said movable contact out of engagement with the stationary contact.

2. In a device of the character described, a base, a transparent tube secured within said base, a conductor secured within said tube and provided with a longitudinal opening and axial bores, a plunger extending through said opening and slidably mounted in the bores, a contact arranged in the opening and secured to said plunger, a stationary contact fixed in the opening of the conductor and insulated from the latter, a coil spring interposed between one end of the opening and the contact on the plunger to force said plunger to carry its contact into engagement with the stationary contact, means to normally hold the plunger inactive until a predetermined temperature has been attained, and an insulated conductor leading outwardly from the stationary contact.

3. In a device of the character described, a base, a transparent tube secured within said base, a conductor secured within said tube and provided with a longitudinal opening and axial bores, a plunger extending through said opening and slidably mounted in the bores, a contact arranged in the opening and secured to said plunger, a stationary contact fixed in the opening of the conductor and insulated from the latter, a coil spring interposed between one end of the opening and the contact on the plunger to force said plunger to carry its contact into engagement with the stationary contact, means to normally hold the plunger inactive until a. predetermined temperature has been attained, an insulated conductor leading outwardly from the stationary contact, a

plate secured to the base and connected to said insulated conductor, and two plates secured to the base and connected to the firstmentioned conductor.

In testimony whereof I aiiix my signature in the presence of two Witnesses.

JOHN M. JOHNSON. Witnesses F. G. Fisormn, L. J. FIsoHnn. 

